• Compression of folder is available in BTRFS system. Multimedia files (such as Video, music, photo files; already compressed) are not suitable for this tweak. However, text files and uncompressed file formats can be further compressed for saving storage space without considerable performance degradation.

check current configuration

$ sudo btrfs property get /volume1/homes
ro=false

If there is no compression property on specific folder, set compression attribute

$ sudo btrfs property set /volume1/homes compression lzo

lzo and zlib properties can be set for compression. The former is fast but less compressed, the latter is opposite. I personally recommend lzo property for compression.